Also, if it's a cable modem, there's usually a web server located at
http://192.168.100.1

Suppose the cable modem does listen to 192.168.100.1 what should the netmask be on my windows computer to be able to access it ? And what should the ip address of the windows computer be ?

Some guesses:

Windows PC 192.168.100.2

Mask either: 255.255.255.0

or

Mask either: 255.255.254.0 ?

or

Mask either: 255.255.0.0 ?

Tried some of these some time.

Never really understood how to compute these netmasks properly, it's a very fokking annoying feature of the internet tech.

Bye,
Skybuck.